Use Forward slash /
to break code into multiline code
Line break means code line change in Python, but you can use forward slash /
to bluff python. You can easily break your code into multiple lines using forward slash in between.
As explained here, the /
as an argument marks the end of arguments that are positional only [see here], i.e. arguments you can't use as keyword parameters. In the case of __eq__[self, value, /]
the slash is at the end, which means that all arguments are marked as positional
only while in the case of your __init__
only self, i.e. nothing, is positional only.
Edit: This was previously only used for built-in functions but since Python 3.8, you can use this in your own functions. The natural companion of /
is *
which allows to mark the beginning of keyword-only arguments.
Example using both:
# a, b are positional-only
# c, d are positional or keyword
# e, f are keyword-only
def f[a, b, /, c, d, *, e, f]:
print[a, b, c, d, e, f]
# valid call
f[10, 20, 30, d=40, e=50, f=60]
# invalid calls:
f[10, b=20, c=30, d=40, e=50, f=60] # b cannot be a keyword argument
f[10, 20, 30, 40, 50, f=60] # e must be a keyword argument
Split a string by forward slash in Python #
Use the str.split[]
method to split a string on the forward slashes, e.g. my_list = my_str.split['/']
. The str.split
method will split the string on each occurrence of a forward slash and will return a list containing the results.
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# ✅ split string on each occurrence of forward slash my_str = 'one/two/three/four' my_list = my_str.split['/'] print[my_list] # 👉️ ['one', 'two', 'three', 'four'] # ✅ split string on each space or forward slash my_str_2 = 'one two/three four five' my_list_2 = my_str_2.replace['/', ' '].split[' '] print[my_list_2] # 👉️ ['one', 'two', 'three', 'four', 'five']
The str.split[] method splits the string into a list of substrings using a delimiter.
The method takes the following 2 parameters:
separator | Split the string into substrings on each occurrence of the separator |
maxsplit | At most maxsplit splits are done [optional]
|
If the separator is not found in the string, a list containing only 1 element is returned.
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my_str = 'one' my_list = my_str.split['/'] # 👇️ ['one'] print[my_list]
If your string starts with or ends with a forward slash, you would get empty string elements in the list.
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my_str = '/one/two/three/four/' my_list = my_str.split['/'] print[my_list] # 👉️ ['', 'one', 'two', 'three', 'four', '']
You can use the filter[]
function to remove any empty strings from the list.
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my_str = '/one/two/three/four/' my_list = list[filter[None, my_str.split['/']]] print[my_list] # 👉️ ['one', 'two', 'three', 'four']
The filter function takes a function and an iterable as arguments and constructs an iterator from the elements of the iterable for which the function returns a truthy value.
If you pass None
for the function argument, all falsy elements of the iterable are removed.
All values that are not truthy are considered falsy. The falsy values in Python are:
- constants defined to be falsy:
None
andFalse
. 0
[zero] of any numeric type- empty
sequences and collections:
""
[empty string],[]
[empty tuple],[]
[empty list],{}
[empty dictionary],set[]
[empty set],range[0]
[empty range].
Note that the filter[]
function returns a filter
object, so we have to use the list[]
class to convert the filter
object to a list.
If you need to split a string on occurrences of a forward slash and another character, replace the forward slash with the other character and split on that character.
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my_str_2 = 'one two/three four five' my_list_2 = my_str_2.replace['/', ' '].split[' '] print[my_list_2] # 👉️ ['one', 'two', 'three', 'four', 'five']
We replaced all occurrences of a forward slash with a space and split the string on each space.
You could achieve the same result by replacing each occurrence of a space with a forward slash and splitting on each forward slash.
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my_str_2 = 'one two/three four five' my_list_2 = my_str_2.replace[' ', '/'].split['/'] print[my_list_2] # 👉️ ['one', 'two', 'three', 'four', 'five']